Presently, when air bag covers are provided in automobiles on the drivers side of the vehicle, the air bag is stored in the steering column behind an air bag cover. During automatic inflation of the air bag, the air bag cover moves away from the steering column to permit its safety function between the steering column and the operator of the vehicle.
Recent practice in the automotive industry is utilization of all plastic fabricated air bag covers. Conventional air bag covers used in conjunction with occupant restraint systems often include various connection systems for attaching the air bag cover to the uninflated air bag container. As those skilled in the art will recognize, such systems normally include a two piece cover construction wherein a first cover portion, usually manufactured from a relatively stiff material, is initially disposed directly over the uninflated air bag container. A second more resilient cover portion is next affixed over the first cover portion and used as the outer decorative cover.
Clark et al. U.S. Pat. No. 4,325,568 discloses a modular occupant restraint system including an inflator, a cushion, a container for the cushion and an air bag cover for the container assembled as a module. Clark et al. utilizes a two piece air bag cover construction.
Gaultier U.S. Pat. No. 5,085,462 discloses an air bag and vehicle horn switch assembly. Gaultier also discloses a conventional two piece cover construction.
Adams et al. U.S. Pat. No. 5,186,490 discloses a cover for a inflatable restraint system for a motor vehicle which contains a slot in the upper wall thereof into which a replaceable thin or membrane type switch assembly in inserted. Adams et al. further discloses an air bag cover having an injection molded thermoplastic upper wall and a soft outer cover exposed to the interior of the vehicle manufactured from urethane, vinyl or polyester. The outer cover completely encompasses and overlaps the upper wall structure and uninflated air bag forming two structures the air bag must exit to carry out its function.
The Embach, U.S. Pat. No. 4,934,735, discloses a device which has inner and outer covers or plates, each of which has split lines which separate the upper walls into upwardly and oppositely opening upper and lower pairs of flaps to permit deployment of the inflatable cushion. A switch assembly is located between either or both pair of flaps and includes one or more membrane switches located between the flaps and respective key pads projecting outwardly of the cover flap for closing respective pairs of circuits on the upper and lower flexible membranes of the membrane switch to each other.
The Heidorn, U.S. Pat. No. 5,308,106, discloses an air bag module cover assembly with a switch subassembly removably attached at a front surface of the assembly.
The Winget, U.S. Pat. No. 5,062,661, discloses a rigid plate attached to the substantially rigid remainder of a front panel of an air bag cover to define a hollow compartment which together move upon manual actuation of a flexible, manually operable diaphragm at the front surface of the front panel. Upon separation from the side panel, the front panel, including the diaphragm, the hollow compartment and a rigid plate move together to permit the inflating air bag to leave the cover. The front panel has a first electrically conductive inner surface for making a circuit path with a corresponding second electrically conductive inner surface of the rigid plate.
The Cooke, II, U.S. Pat. No. 5,344,185, discloses an air bag cover having a replaceable horn switch and a removable cover band.
Some of the above switches are relatively small and oftentimes inaccessible for drivers who have large hands or for drivers who have limited manual dexterity. Also, such switches extend, at least to a limited extent, above the exterior surface of the air bag cover and may strike the occupant upon air bag inflation. Consequently, there is a need for a horn switch device which is incorporated in an air bag cover, is relatively easy to service and which is actuable over a relatively large surface area of the air bag cover and which does not extend above the generally planar exterior surface of the air bag cover.